1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250
use crossbeam::sync::TreiberStack; use world::{Component, EntitiesRes, Entity, World}; /// Like `EntityBuilder`, but inserts the component /// lazily, meaning on `maintain`. /// If you need those components to exist immediately, /// you have to insert them into the storages yourself. pub struct LazyBuilder<'a> { /// The entity that we're inserting components for. pub entity: Entity, /// The lazy update reference. pub lazy: &'a LazyUpdate, } impl<'a> LazyBuilder<'a> { /// Inserts a component using `LazyUpdate`. pub fn with<C>(self, component: C) -> Self where C: Component + Send + Sync, { let entity = self.entity; self.lazy.execute(move |world| { world.write_storage::<C>().insert(entity, component); }); self } /// Finishes the building and returns the built entity. /// Please note that no component is associated to this /// entity until you call `World::maintain`. pub fn build(self) -> Entity { self.entity } } trait LazyUpdateInternal: Send + Sync { fn update(self: Box<Self>, world: &World); } impl<F> LazyUpdateInternal for F where F: FnOnce(&World) + Send + Sync + 'static, { fn update(self: Box<Self>, world: &World) { self(world); } } /// Lazy updates can be used for world updates /// that need to borrow a lot of resources /// and as such should better be done at the end. /// They work lazily in the sense that they are /// dispatched when calling `world.maintain()`. /// Please note that the provided methods take `&self` /// so there's no need to fetch `LazyUpdate` mutably. /// This resource is added to the world by default. #[derive(Default)] pub struct LazyUpdate { stack: TreiberStack<Box<LazyUpdateInternal>>, } impl LazyUpdate { /// Creates a new `LazyBuilder` which inserts components /// using `LazyUpdate`. This means that the components won't /// be available immediately, but only after a `maintain` /// on `World` is performed. /// /// ## Examples /// /// ``` /// # use specs::prelude::*; /// # let mut world = World::new(); /// struct Pos(f32, f32); /// /// impl Component for Pos { /// type Storage = VecStorage<Self>; /// } /// /// # let lazy = world.read_resource::<LazyUpdate>(); /// # let entities = world.entities(); /// let my_entity = lazy /// .create_entity(&entities) /// .with(Pos(1.0, 3.0)) /// .build(); /// ``` pub fn create_entity(&self, ent: &EntitiesRes) -> LazyBuilder { let entity = ent.create(); LazyBuilder { entity, lazy: self } } /// Lazily inserts a component for an entity. /// /// ## Examples /// /// ``` /// # use specs::prelude::*; /// # /// struct Pos(f32, f32); /// /// impl Component for Pos { /// type Storage = VecStorage<Self>; /// } /// /// struct InsertPos; /// /// impl<'a> System<'a> for InsertPos { /// type SystemData = (Entities<'a>, Read<'a, LazyUpdate>); /// /// fn run(&mut self, (ent, lazy): Self::SystemData) { /// let a = ent.create(); /// lazy.insert(a, Pos(1.0, 1.0)); /// } /// } /// ``` pub fn insert<C>(&self, e: Entity, c: C) where C: Component + Send + Sync, { self.execute(move |world| { world.write_storage::<C>().insert(e, c); }); } /// Lazily inserts components for entities. /// /// ## Examples /// /// ``` /// # use specs::prelude::*; /// # /// struct Pos(f32, f32); /// /// impl Component for Pos { /// type Storage = VecStorage<Self>; /// } /// /// struct InsertPos; /// /// impl<'a> System<'a> for InsertPos { /// type SystemData = (Entities<'a>, Read<'a, LazyUpdate>); /// /// fn run(&mut self, (ent, lazy): Self::SystemData) { /// let a = ent.create(); /// let b = ent.create(); /// /// lazy.insert_all(vec![(a, Pos(3.0, 1.0)), (b, Pos(0.0, 4.0))]); /// } /// } /// ``` pub fn insert_all<C, I>(&self, iter: I) where C: Component + Send + Sync, I: IntoIterator<Item = (Entity, C)> + Send + Sync + 'static, { self.execute(move |world| { let mut storage = world.write_storage::<C>(); for (e, c) in iter { storage.insert(e, c); } }); } /// Lazily removes a component. /// /// ## Examples /// /// ``` /// # use specs::prelude::*; /// # /// struct Pos; /// /// impl Component for Pos { /// type Storage = VecStorage<Self>; /// } /// /// struct RemovePos; /// /// impl<'a> System<'a> for RemovePos { /// type SystemData = (Entities<'a>, Read<'a, LazyUpdate>); /// /// fn run(&mut self, (ent, lazy): Self::SystemData) { /// for entity in ent.join() { /// lazy.remove::<Pos>(entity); /// } /// } /// } /// ``` pub fn remove<C>(&self, e: Entity) where C: Component + Send + Sync, { self.execute(move |world| { world.write_storage::<C>().remove(e); }); } /// Lazily executes a closure with world access. /// /// ## Examples /// /// ``` /// # use specs::prelude::*; /// # /// struct Pos; /// /// impl Component for Pos { /// type Storage = VecStorage<Self>; /// } /// /// struct Execution; /// /// impl<'a> System<'a> for Execution { /// type SystemData = (Entities<'a>, Read<'a, LazyUpdate>); /// /// fn run(&mut self, (ent, lazy): Self::SystemData) { /// for entity in ent.join() { /// lazy.execute(move |world| { /// if world.is_alive(entity) { /// println!("Entity {:?} is alive.", entity); /// } /// }); /// } /// } /// } /// ``` pub fn execute<F>(&self, f: F) where F: FnOnce(&World) + 'static + Send + Sync, { self.stack.push(Box::new(f)); } pub(super) fn maintain(&mut self, world: &World) { let lazy = &mut self.stack; while let Some(l) = lazy.pop() { l.update(&world); } } } impl Drop for LazyUpdate { fn drop(&mut self) { // TODO: remove as soon as leak is fixed in crossbeam while self.stack.pop().is_some() {} } }